Table 1.

Description of Some Genetically Modified Bacterial Strains Used for Tumor Therapy

Bacteria	Attenuated Strain	Description	References
Bifidobacterium	B. longum 105-A	Effective delivery of spectinomycin resistance gene	[49]
Clostridium	C. novyi-NT	Exhibits strong tumor-specific colonization and proteolytic features. Curing of 50% HTC116 xenograft and tumor regression as performed by COBALT technique	[50]
	C. beijerinckii NCIMB 8052	Expression of dihydropteridine gene, catalyzing the prodrug CB1955, and in vivo tumor eradication by 22-fold	[51]
	C. sporogenes NCIMB 10696	Insertion of E. coli Cod A gene expressing cysteine deaminase. This strain presents outstanding anticancer effects when colonized in SCCV11-tumor bearing mice followed by 5-fluorocytosine injection.	[52]
E. coli	E. coli (BM2710)	Insertion of inv gene derived from Y. pseudotuberculosis in the plasmid produces invasin which promotes the phagocytosis of the cell by mammalian cells	[53]
Salmonella typhimurium	ΔppGpp	Modified strain with the property of downregulating endotoxin genes. After injection systematically, virulent to mouse, suitable vector for targeting the delivery of antitumor molecules	[54]
	VNP20009	Possess purine dependent colonization behavior. This strain possesses a relatively better safety profile as it has been made to reduce septic shock	[55]
	A1-R	Possesses arginine and leucine dependent colonization behavior. In mouse models, inhibits the growth of different cancer types. This strain also helps to alter the cell cycle.	[56]